The Trial of a Time Lord, Part Two (The Mysterious Planet) Season 23 - Episode 2

The Doctor is saved from the stoning in the nick of time and taken to see the Immortal who wants to use the Doctors far greater knowledge to his advantage. Meanwhile, Peri is taken before Queen Katryca of the local tribe and told that she is to become part of the tribe and take many husbands because there is a shortage of women.